$ dig +trace roclinux.cn ; <<>> DiG 9.2.4 <<>> +trace roclinux.cn ;; global options: printcmd. 335937 IN NS l.root-servers.net.. 335937 IN NS b.root-servers.net.. 335937 IN NS d.root-servers.net.. 335937 IN NS k.root-servers.net.. 335937 IN NS h.root-servers.net.. 335937 IN NS j.root-servers.net.. 335937 IN NS a.root-servers.net.. 335937 IN NS e.root-servers.net.. 335937 IN NS c.root-servers.net.. 335937 IN NS m.root-servers.net.. 335937 IN NS g.root-servers.net.. 335937 IN NS i.root-servers.net.. 335937 IN NS f.root-servers.net.;; Received 400 bytes from 10.23.0.231#53(10.23.0.231) in 0 ms //从本地DNS查找到根域DNS列表cn. 172800 IN NS c.dns.cn.cn. 172800 IN NS a.dns.cn.cn. 172800 IN NS b.dns.cn.cn. 172800 IN NS e.dns.cn.cn. 172800 IN NS ns.cernet.net.cn. 172800 IN NS d.dns.cn.;; Received 292 bytes from 192.228.79.201#53(b.root-servers.net) in 460 ms //选择了b.root-servers.net这台根域DNS来查找cn.域DNS列表roclinux.cn. 21600 IN NS ns11.edong.com.roclinux.cn. 21600 IN NS ns12.edong.com.;; Received 76 bytes from 203.119.27.1#53(c.dns.cn) in 0 ms //选择了c.dns.cn这台cn.域DNS服务器来查找roclinux.cn的DNS列表roclinux.cn. 3600 IN A 116.255.245.206roclinux.cn. 3600 IN NS ns12.edong.com.roclinux.cn. 3600 IN NS ns11.edong.com.;; Received 124 bytes from 61.147.124.145#53(ns11.edong.com) in 104 ms //最终查找到A记录联系客服
